A system for detecting overloads of a motor comprises a motor configured to receive power via a lead line, a first sensing device configured to sense a temperature of a motor, and a second sensing device electrically coupled to the motor and configured to detect a target current of the motor and trigger a contact of the lead line associated with second sensing device when the target current equals or exceeds a trip value.

An electrical system includes first, second and third busses; a first interrupter electrically connected between the first and second busses; at least one of a shorting apparatus operatively associated with the first or second bus, and the first interrupter comprising a trip coil; a current sensor to sense a fault current flowing in the first bus and responsively output a first signal; a number of light sensors to sense an arc flash operatively associated with a number of the first, second or third busses and responsively output a second signal; a second interrupter electrically connected between the second and third power busses and output a third signal; and a circuit to invert the third signal to provide a fourth signal, and to operate the at least one of the shorting apparatus and the trip coil responsive to an AND of the first, second and fourth signals.

A method for analyzing power quality events in an electrical system includes processing electrical measurement data from or derived from energy-related signals captured by at least one of a plurality of metering devices in the electrical system to generate or update a plurality of dynamic tolerance curves. Each of the plurality of dynamic tolerance curves characterizes a response characteristic of the electrical system at a respective metering point of a plurality of metering points in the electrical system. Power quality data from the plurality of dynamic tolerance curves is selectively aggregated to analyze power quality events in the electrical system.

Various implementations described herein are directed to a methods and apparatuses for disconnecting, by a device, elements at certain parts of an electrical system. The method may include measuring operational parameters at certain locations within the system and/or receiving messages from control devices indicating a potentially unsafe condition, disconnecting and/or short-circuiting system elements in response, and reconnection the system elements when it is safe to do so. Certain embodiments relate to methods and apparatuses for providing operational power to safety switches during different modes of system operation.

A modular intelligent electronic overload device that requires only a single configuration file to describe the device with all of the available options. Furthermore, the modular intelligent electronic overload device contains embedded application files that provide commonly used control algorithms into the non-volatile memory of the modular intelligent electronic overload device that can be accessed by a user to configure the device without the need for a personal computer. Finally, the modular intelligent electronic overload device configuration parameters can be stored to virtual non-volatile memory contained in an associated user interface device, allowing for easy replacement of the modular intelligent electronic overload device.

A switching element driving circuit includes a current detection unit that outputs a driving stop signal based on a level of current flowing through the switching element, and first and second control elements each connected to a control terminal of the switching element. A comparator controls the first control element based on a result of comparison of an output voltage of the driving circuit main unit with a first reference voltage. A differential amplifier drives the second control element in accordance with a voltage difference between the output voltage of the driving circuit main unit and a second reference so as to maintain the output voltage equal to the second reference voltage. An operation stopping unit stops the comparator and the differential amplifier to drive the first and second control elements, respectively, in response to the driving stop signal.

An electrical sensor is described. The electrical sensor including an electrical signal input configured to receive an electrical signal, an alarm, one or more inputs configured to set a configuration value and at least one display configured to display said configuration value. The monitor is coupled with the electrical signal input, the alarm, the display, and the one or more inputs. Further, the monitor is configured to determine a characteristic of the electrical signal received on the electrical signal input. The monitor is configured to activate the alarm based on the configuration value set by the one or more inputs and the characteristic of the electrical signal. And, the monitor configured to generate at least one display signal based on the configuration value to be used by the at least one display to display the configuration value.

A device for detecting a fault in an AC supply comprising a detection circuit for detecting a fault in an AC supply to a load and providing a corresponding output. A disconnect circuit disconnects the load from the supply in response to an output from the detection circuit. The device also includes a generator of intermittent test pulses, and a test circuit coupled to the detection circuit and containing a first solid state switch. Each test pulse turns on the solid state switch for the duration of the test pulse so that a current simulating the fault flows intermittently in the test circuit and a corresponding output is provided by the detection circuit. The device further comprising means to disable the disconnect circuit in response to each test pulse.

An advance warning lightning electromagnetic pulse (LEMP) storm detection device, system, and method for automatically protecting, disconnecting, and isolating electronic equipment in anticipation of a potential storm, thereby preventing damage to electronics susceptible to power surges caused by lightning strikes or earth ground fault events. The storm detection device can include a coaxial isolation switch, a radio receiver, a controller having a processor, wherein the controller further includes an isolation detection unit. In addition, the storm detection device can further include a drive motor, one or more input electrical contacts, and one or more output electrical contacts engaged with the input electrical contacts. Further, wherein in response to the radio receiver detecting one or more lightning strikes, the controller operates the drive motor to disengage the input electrical contacts and output electrical contacts from each other.

An advance warning lightning electromagnetic pulse (LEMP) storm detection device, system, and method for automatically protecting, disconnecting, and isolating electronic equipment in anticipation of a potential storm, thereby preventing damage to electronics susceptible to power surges caused by lightning strikes or earth ground fault events. The storm detection device can include a coaxial isolation switch, a radio receiver, a controller having a processor, wherein the controller further includes an isolation detection unit. In addition, the storm detection device can further include a drive motor, one or more input electrical contacts, and one or more output electrical contacts engaged with the input electrical contacts. Further, wherein in response to the radio receiver detecting one or more lightning strikes, the controller operates the drive motor to disengage the input electrical contacts and output electrical contacts from each other.